Cement additive

ABSTRACT

A cement additive comprising a polycarboxylic acid type copolymer and/or a salt thereof and a polyalkylene glycol derivative, wherein said polycarboxylic acid type copolymer contains one or more species of copolymers composed of at least an unsaturated polyalkylene glycol type monomer and an unsaturated mono- or dicarboxylic acid type monomer as their monomer components. Concretes in which the additive is used have excellent flow, without significant retarding effect, and a low air entrainment. When used with concrete for steam curing it allows earlier removal of form work.

This invention relates to a cement additive and more particularly, to acement additive used to improve the fluidity and appearance of strengthof cement slurry, cement paste, mortar and concrete.

Various cement additives comprising polycarboxylic acid type copolymershave been proposed for enhancing the fluidity and flowability ofconcrete. While this works well for ordinary concretes, it is not soeffective when high strength and high durability are required, as suchcopolymers tend to entrain an excess of air and retard setting.

In relation to pre-formed concrete products, it is strongly desired todecrease the total time spent in a form and to prevent defects when theform is removed. For such products, good appearance is also highlydesirable, when the form is removed after steam curing. Variouspolycarboxylate materials to achieve this have been proposed, but nonehave been entirely satisfactory, causing such problems as retardedsetting and low fluidity.

It has now been found that a cement additive containing a polycarboxylicacid type copolymer and a polyalkylene glycol derivative having aspecific molecular structure can alleviate and sometimes completelyremove all the above-mentioned problems, by having a high dispersingability for various concretes, improving and retaining the fluidity ofconcrete, and also making it possible to increase the strength ofpre-formed concrete, such that form removal after steam curing can becarried out relatively early, giving a product with low aeration.

The invention therefore provides a cement additive containing apolycarboxylic acid type copolymer and/or the salts thereof and apolyalkylene glycol derivative, said polycarboxylic acid type copolymercontains at least one species of copolymer, the monomers of whichcopolymer comprise at least an unsaturated polyalkylene glycol typemonomer (A) and an unsaturated mono- or dicarboxylic acid type monomer(B).

The invention also relates to a cement additive, wherein thepolycarboxylic acid type copolymers are copolymers which additionallyinclude as monomer components an unsaturated polyalkylene glycol estertype monomer (C) and/or a monomer (D) polymerizable with theabove-mentioned monomers (A) and (B), or with the monomers (A), (B) and(C).

The invention further relates to the above-mentioned cement additive,wherein the monomer (A) is a compound according to the general formula(1):

wherein R¹, R² and R³ are each independently hydrogen or methyl,provided that not all are methyl; R⁴ is —CH₂O—, —(CH₂)₂O—, —C(CH₃)₂O— or—O—; the total carbon number of R¹, R², R³ and R⁴ is 3; R⁵O is one ormore species of C₂-C₄ oxyalkylene groups, and in the case of two or morespecies may be block or random; R⁶ is hydrogen or a C₁-C₂₂ alkyl, phenylor C₁-C₁₈ alkylphenyl group; p is an integer from on average 1to 100;

the monomer (B) is a compound according to the general formula (2):

wherein R⁷ and R⁸ are each independently hydrogen or methyl; R⁹ ishydrogen, methyl or —(CH₂)_(q)COOM²; R¹⁰ is —(CH2)_(r)—; q and r areeach independently an integer from 0 to 2; M¹ and M² are a monovalentmetal, a divalent metal, ammonium or an organic amine;

the monomer (C) is a compound according to the general formula (3):

wherein R¹¹ and R¹² are each independently hydrogen, methyl or(CH₂)_(u)COOM³, u is an integer from 0 to 2, M³ is a monovalent metal, adivalent metal, ammonium or an organic amine; R¹³O is one or morespecies of C₁-C₄ oxyalkylene groups, and in the case of two or morespecies may be block or random; R¹⁴ is hydrogen or a C₁-C₂₂ alkyl,phenyl or C₁-C₂₂ alkylphenyl group; s is an integer from 0 to 2; t is aninteger an average from 1 to 300; and

the monomer (D) is a compound according to the general formula (4):

wherein R¹⁵, R¹⁶, R¹⁸ and R¹⁹ are each independently hydrogen or methyl,provided that not all are methyl, R¹⁷O is one or more species of C₂-C₄oxyalkylene groups, and in the case of two or more species may be blockor random; w is an integer an average from 1 to 300; v and x are eachindependently an integer from 0 to 2.

The invention also relates to the abovementioned cement additive,wherein the composition ratios of the monomers (A) and (B) in thepolycarboxylic acid-type copolymers are 30-100 mole % based on the totalmole amount of the monomers, and the average molecular weight of saidpolycarboxylic acid-type copolymer is from 3,000-100,000 (all molecularweights (MW referred to herein were measured by gel permeationchromatography with polyethylene glycol as standard).

The invention also relates to the abovementioned cement additive,wherein the average molecular weight of the polyalkylene glycolderivatives is from 1,000-100,000, in which the alkylene is one or moreC₂-C₄ species, and the terminal groups of the polyalkylene glycol ishydrogen or a C₁-C₁₈ is alkyl or phenyl group.

Further, the invention relates to the abovementioned cement additivecontaining 100 weight parts of the polycarboxylic acid type copolymersand 10-50 weight parts of the polyalkylene glycol derivatives.

Also, the invention relates to the above mentioned cement additive,wherein the amount of the polycarboxylic acid type copolymers added tocement is 0.05-1.0% by weight based on the weight of cement, and theamount of the polyalkylene glycol derivative added to cement is0.00-0.5% by weight based on the weight of cement.

Further, the invention relates to use of abovementioned cement additivein high strength concrete.

The invention also relates to the use of the abovementioned cementadditive in the formation of pre-formed concrete articles by steamcuring.

The invention further provides a method of preparation of ahigh-strength concrete mix, comprising the incorporation in the mix of acement additive as hereinabove described.

The invention further provides a method of preparing of a concrete mixadapted to be used for the manufacture of articles by steam curing,comprising the incorporation in the mix of a cement additive ashereinabove described.

In a cement additive according to the invention, the monomers (A) aretypically compounds according to the abovementioned general form (1),more specifically, the compounds in which 1-100 mole of an alkyleneoxide is added to an unsaturated alcohol such as 3-methyl-2-buten-1-ol,3-methyl-3-buten-1-ol, 2-methyl-3-buten-2-ol. One or more species ofunsaturated alcohol may be used.

Examples of monomers (B) include compounds according to general formula(2), more specifically, for example, acrylic acid, methacrylic acid,crotonic acid, maleic acid, fumaric acid, itaconic acid and citraconicacid. One or more species of these may be used.

Monomers (C) are typically compounds according to general formula (3).Specific examples include unsaturated polyalkylene glycol monoester typemonomers such as polyethylene glycol monoesters, polypropylene oxidemonoesters, monoesters of polyethylene glycol/polypropylene oxidecopolymers, derivatives in which a terminal hydrogen of these glycols isetherified, and the like, such as triethylene glycol monoacrylate,polyethylene glycol (MW 200) monoacrylate, polyethylene glycol (MW 400)monoacrylate, polyethylene glycol (MW 600) monoacrylate, polyethyleneglycol (MW 1000) monoacrylate, polyethylene glycol (MW 2000)monoacrylate, polyethylene glycol (MW 4000) monoacrylate, polyethyleneglycol (MW 6000) monoacrylate, triethylene glycol monomethacrylate,polythylene glycol (MW 200) monomethacrylate, polyethylene glycol (MW400) monomethacrylate, polyethylene glycol (MW 600) monomethacrylate,polyethylene glycol (MW 1000) monomethacrylate, polyethylene glycol (MW2000) monomethacrylate, polyethylene glycol (MW 4000) monomethacrylateand polyethylene glycol (MW 6000) monomethacrylate, and one or morespecies of these may be used.

The monomers (D) are typically compounds according to general formula(4), specific examples including unsaturated polyalkylene glycol diestertype monomers and/or styrene, styrenesulfonic acid and/or the saltsthereof acrylic acid alkyl esters (alkyl of C₂₂ maximum) methacrylicacid alkyl ester (alkyl of C₂₂ maximum), maleic anhydride, maleic acidmonoesters (akyl of C₂₂ maximum), and/or alkylene glycol of C₃ maximumand 1-300 alkylene glycol units, maleic acid diester (alkyl of C₂₂maximum and/or alkylene glycol of C₃ maximum and 1-300 alkylene glycolunits, vinyl acetate, acrylamide and acrylamide methylpropansulfonicacid and/or the salts thereof.

Specific examples include styrene, styrenesulfonic acid and/or the saltsthereof, acrylic acid methyl ester, acrylic acid ethyl ester, acrylicacid butyl ester, methacrylic acid methyl ester, methacrylic acid ethylester, methacrylic acid butyl ester, maleic anhyride, maleic acid methylmonoester, maleic acid ethyl monoester, maleic acid methyl diester,maleic acid ethyl diester, vinyl acetate, acrylamide, acrylamidemethylpropansulfonic acid and/or the salts thereof, methallyl sulfonicacid and/or the salts thereof. One or more species of these may be used.

Specific non-limiting examples of polycarboxylic acid type copolymersare those described in JP, A, H5-306152, JP, A, H6-211949, JP, A,H9-286647 and JP, A, H10-236858.

The composition ratio of the monomers (A) and (B) in the polycarboxylicacid type copolymers in the invention to total amount of the monomers ispreferably 30-100 mole %, and the average molecular weight is preferably3,000-100,000.

In the polyalkylene glycol derivatives of the invention, the averagemolecular weight is 1,000-150,000, preferably 1,000-100,000, morepreferably 4,000-50,000, the alkylene is one or more C₂-C₄ species, andit may be block or random in the case of 2 or more species, the terminalgroups of polyalkylene glycol are hydrogen, C₁₈ maximum alkyl or phenylgroups.

In a cement additive of the invention, the preferred proportions are 100weight parts of polycarboxylic acid type copolymers and 10-50 weightparts of polyalkylene glycol derivatives.

A cement additive of the invention is preferably used in such a quantitythat polycarboxylic acid type copolymers are present in the proportion0.05-1.0% by weight based on cement weight and polyalkylene glycolderivatives are present in the proportion 0.005-0.5% by weight based oncement weight. However, the amount of the cement additive according tothe invention to be used can be appropriately determined according to acement composition used, it basically being the amount which isnecessary to attain the desired strength development and improved timeto form removal after steam curing, and it is possible that suitableproportions outside these limits may be found.

A cement additive according to the invention may be used for stiffconsistency concrete, plastic concrete, high fluidity concrete, highstrength concrete, cement paste as generally used, mortar, grout,concrete and the like, although the beneficial effects of the inventionare most noticeable in high strength concrete in which the water/cementratio is low.

A cement additive according to the invention may be mixed, if desired,with other additives to expand its versatility. Typical examples ofother additives are conventional water reducing agents (lignosulfonate,oxycarboxylate, polyalkylsulfonate, polycarboxylate), aircontent-regulating agents, drying shrinkage reducing agents,accelerators, retarders, foaming agents, anti-foaming agents, anti-rustagents, set acceleration agents, high early-strengthening agents,efflorescence-inhibiting agents, bleeding inhibitors, pumping aids, andwater-soluble polymers.

A cement additive according to the invention exhibits a high dispersingability of a degree never obtained by use only of polycarboxylicacid-type copolymers to various concretes such as ordinary concrete,high strength concrete and steam curing concrete. Without restrictingthe scope of the invention in any way, it is believed that this is theresult of a synergistic effect of the polycarboxylic acid typecopolymers and the polyalkylene glycol derivatives. It both enhances thefluidity of concrete and maintains this fluidity, thereby making itpossible to increase the strength development and decrease the time forform removal after steam curing. The latter is particularly valuable inthat it permits economies such as the reduction of time spent in a formused and the reduction of defects in concrete products manufactured in aconcrete factory.

The invention is now further illustrated by the following non-limitingexamples wherein are used the cement additives containing polycarboxylicacid type copolymers and polyalkylene glycol derivatives according tothe invention.

EXAMPLES

The compositions of the polycarboxylic acid type copolymers in thecement additives used in the examples and in the comparative examplesare shown in Table 1. Said polycarboxylic acid type copolymers can beobtained by known polymerization methods described in, for example, JP,A, H5-306152, JP, A, H6-211949, JP, A, H9-286647 and JP, A, H10-236858.The polyalkylene glycol derivatives in the cement additives used in theexamples and in the comparative examples are also shown in Table 2.

In order to illustrate the effect of these cement additives, theconcrete compositions (shown in Table 3) are designed to have slump of18.5±1 cm and air content 4.5%. The total quantity of materials in eachcase is 80 liters, and all the materials are added to a 100 literpan-type forced mixing mixer, and mixed for 120 sec, to give theconcrete compositions. The concrete compositions thus obtained aremeasured for slump, air content, setting time and compressive strength.Further, the compressive strength in the case of accelerating theappearance of strength by steam curing was measured.

1) Slump: measured according to JIS A 1101,

2) Air content: measured according to JIS A 1128,

3) Setting time: measured according to JIS A 6204 Supplement 1,

4) Compressive strength

Ordinary curing: measured according to JIS A 1108.

Steam curing: the sample is pre-cured at 20° C. for 2 hr, then warmed to65° C. in 2 hrs 30 min, kept at 65° C. for 4 hrs. After allowing to coolto 20° C. over 4 hrs, the testing is carried out according to, JIS A1108.

(Materials Used)

Mixing water: tap water,

Cement: ordinary portland cement (density 3.16 g/cm³).

Fine aggregate: Oi River pit sand (specific gravity 2.59. FM=2.74),

Coarse aggregate: Oume crushed stone (specific gravity 2.65. MS[mediansize?]=20 mm).

The results of the above measurement are shown in Table 4. In the Table,the examples 1-13 and the comparative examples 1-4 are for the resultsobtained from the ordinary cement, and the examples 14, 15 and thecomparative examples 5, 6 are those obtained from the high strengthconcrete.

The examples 1-7 show the cases in which the type of the polycarboxylicacid type copolymers is changed, and the examples 1and 8-13 are thecases in which the type of the polyalkylene glycol derivatives ischanged.

The comparative examples 1and 5 show the cases in which a polyalkyleneglycol derivative is not used, and the comparative examples 2-4 and 6are the cases in which compounds other than the polycarboxylic acid typecopolymers in the invention are used.

As is evident from the comparison between the comparative example 1andthe examples 1-13, and from the comparison between the comparativeexample 5 and the examples 14 and 15, the ordinary concrete and the highstrength concrete, in which the cement additives together with thepolyalkylene glycol derivatives of the invention are used, both show atendency to accelerate setting, whereby the slump values are large(fluidity) and their slump lowering over 60 min is small (highflowability), demonstrating a preferable compressive strength both forordinary curing and steam curing.

The comparative examples 2-4 and 6 are those in which compounds otherthan the polycarboxylic acid type copolymers in the invention are used,though in these examples the development of compressive strength is notsufficient, because there is demonstrated a retardation of setting.

TABLE 1 Type of monomer and composition ratio Type of Polycar- Monomer(A) Monomer (B) Monomer (C) Monomer (D) boxylic Mole Mole Mole MoleAverage Acid-type ratio AG ratio ratio AG ratio Molecular copolymer (%)Type No. (%) Type (%) Type No. (%) Type Weight PCA-1 1.5 Polyethyleneglycol 50 1 Maleic acid — — — — — 20000 mono-vinyl ether PCA-2 1.52-Methyl 2-propen- 50 1 Maleic acid — — — — — 30000 1-ol alkylene oxideadduct PCA-3 1.5 Polyethylene glycol 50 1 Maleic acid 0.2 Polyethyleneglycol 75 — — 35000 mono-vinyl ether maleic acid ester PCA-4 1.5Polyethylene glycol 50 1 Maleic acid 0.3 Polyethylene glycol 25 0.1Maleic anhydride 24000 polypropylene maleic acid ester glycol allylether PCA-5 1.5 Polyethylene glycol 12 1 Maleic acid — — — 0.2 Styrene32000 allyl ether PCA-6 1.5 2-Methyl 2-propen- 25 1 Acrylic acid — — —0.2 Acrylamide 27000 1-ol alkylene oxide methylpropan sulfonic adductacid PCA-7 1.5 2-Methyl 2-propen- 75 1 Acrylic acid — — — 0.2Polyethylene glycocl 75000 1-ol alkylene oxide dimethacrylic acid adductester P-1 1 2-Methyl 2-propen- 50 1 Maleic acid 2 Polyethylene glycol 25— — 30000 1-ol alkylene oxide maleic acid ester adduct P-2 1Polyalkylene glycol 50 1 Maleic acid 2 Polyethylene glycol 25 — — 28000monovinyl eher methacrylic acid ester P-3 — — — 1 Acrylic acid 2Polyethylene glycol 100  — — 28000 methacrylic acid ester

TABLE 2 Average molecular Sample mark Component name of polyalkyleneglycol weight PAG-1 Polyethylene glycol 4000 PAG-2 Polyethylene glycol6000 PAG-3 Polyethylene glycol 10000  PAG-4 Polyethylene glycol 20000 PAG-5 Polyethylene glycol 50000  PAG-6 Polyethylene glycol-polypropyleneglycol block 4000 polymer PAG-7 Polyethylene glycol oleic acid ester 5000

TABLE 3 (Blend) Type of W/C s/a Unit amount (Kg/m³) Concrete (%) (%) W CS G Ordinary 50 46 160 320 823 993 Concrete High-strength 35.6 44 160450 741 968 concrete

TABLE 4 (Concrete test) Polycarboxylic acid type copolymer PAG AmountAmount added added Slump (cm) Air content (%) Type of blend No. Type (wt%) Type (wt %) Just after 60 min later Just after 60 min later ExampleOrdinary 1 PCA-1 0.2 PAG-4 0.03 19.0 15.0 4.5 4.5 Concrete 2 PCA-2 0.2PAG-4 0.03 15.5 16.0 4.4 4.4 3 PCA-3 0.2 PAG-4 0.03 18.0 11.5 4.6 4.5 4PCA-4 0.2 PAG-4 0.03 18.5 19.0 4.4 4.5 5 PCA-5 0.2 PAG-4 0.03 18.0 15.04.4 4.3 6 PCA-6 0.2 PAG-4 0.03 18.0 15.0 4.6 4.5 7 PCA-7 0.2 PAG-4 0.0318.5 18.5 4.3 4.4 8 PCA-1 0.2 PAG-1 0.05 18.0 15.0 4.2 4.3 9 PCA-1 0.2PAG-2 0.05 18.0 15.0 4.4 4.5 10 PCA-1 0.2 PAG-3 0.05 18.5 15.0 4.5 4.611 PCA-1 0.2 PAG-5 0.05 18.0 15.0 4.5 4.3 12 PCA-1 0.2 PAG-6 0.03 18.515.0 4.6 4.4 13 PCA-1 0.2 PAG-7 0.03 18.5 15.0 4.6 4.5 High 14 PCA-1 0.2PAG-4 0.03 19.0 15.0 4.5 4.5 Strength 15 PCA-2 0.2 PAG-4 0.03 18.5 16.04.4 4.4 Concrete Comparative Ordinary 1 PCA-1 0.3 — — 17.5 6.0 4.4 4.0Example Concrete 2 P-1 0.2 PAG-4 0.05 18.5 14.5 4.3 5.7 3 P-2 0.2 PAG-40.05 19.0 13.5 4.5 5.9 4 P-3 0.2 PAG-4 0.05 18.5 14.0 4.5 5.9 High 5PCA-1 0.3 — — 13.0 6.0 4.4 4.0 strength 6 P-3 0.3 PAG-4 0.05 18.5 14.04.5 5.9 concrete Compressive strength Setting time (N/mm²) (min)Standard curing steam curing Type of blend No. Start End age 3 days age7 hrs Example Ordinary 1 355 450 25.0 27.6 Concrete 2 350 450 25.4 27.93 355 450 25.2 27.6 4 355 460 24.5 27.1 5 355 450 25.6 28.3 6 355 45025.2 27.4 7 355 450 24.1 29.2 8 355 450 25.2 28.4 9 355 450 25.6 28.3 10355 450 25.4 28.3 11 355 450 25.3 28.3 12 355 450 26.7 28.4 13 355 45026.7 27.1 High 14 300 395 36.4 39.1 Strength 15 305 390 36.2 39.0Concrete Comparative Ordinary 1 380 485 20.4 23.4 Example Concrete 2 355450 22.4 23.5 3 355 455 22.6 23.8 4 380 470 22.7 23.5 High 5 340 49531.0 35.2 strength 6 350 445 31.5 36.0 concrete

What is claimed is:
 1. A cement additive comprising: (a) apolycarboxylic acid copolymer and/or a salt thereof and a polyalkyleneglycol compound, wherein said polycarboxylic acid copolymer contains atleast one species of copolymer derived from at least an unsaturatedpolyalkylene glycol ether monomer (A) and an unsaturated mono- ordicarboxylic acid monomer (B) as its monomer component; or (b) apolycarboxylic acid copolymer and/or a salt thereof and a polyalkyleneglycol compound, wherein said polycarboxylic acid copolymer contains atleast one species of copolymer derived from at least an unsaturatedpolyalkylene glycol ether monomer (A) and an unsaturated mono- ordicarboxylic acid monomer (B) as its monomer component and saidpolycarboxylic add copolymer is additionally derived from an unsaturatedpolyalkylene glycol ester monomer (C) and/or monomer (D), which iscopolyermerizable with monomers (A) and (B), or with monomers (A), (B)and (C); wherein for (a) and (b), the monomer (A) is a compoundaccording to general formula (1)

wherein R¹, R² and R³ are each independently hydrogen or methyl,provided that not all are methyl; R⁴ is —CH₂O—, —(CH₂)₂O—, —C(CH₃)₂O— or—O—; the total carbon number of R¹, R², R³ and R⁴ is 3; R⁵O is one ormore species of C₂-C₄ oxyalkylene groups, and, in the case of two ormore species is optionally block or random; R⁸ is hydrogen or a C₁-C₂₂alky, phenyl or C₁-C₁₈ alkylphenyl group; p is an integer from onaverage 1 to 100, the monomer (B) is a compound according to generalformula (2):

wherein R⁷ and R⁸ are each independently hydrogen or methyl; R⁹ ishydrogen, methyl or —(CH₂)_(q)COOM²; R¹⁰ is —(CH₂)_(r)—, q and r areeach independently an integer from 0 to 2, M¹ and M² are a monovalentmetal, a divalent metal, ammonium or an organic amine; the monomer (C)is a compound according to general formula (3);

wherein R¹¹ and R¹² are each independently hydrogen, methyl or(CH₂)_(u)COOM³, u is an integer from 0 to 2, M³ is a monovalent metal, adivalent metal, ammonium or an organic amine; R¹³O is one or morespecies of C₂-C₄ oxyalkylene groups, and, in the case of two or morespecies, is optionally block or random; R¹⁴ is a C₁-C₂₂ hydrogen or analkyl, phenyl or C₁-C₂₂ alkylphenyl group; s is an integer from 0 to 2;t is an integer an average from 1 to 300; and the monomer (D) is acompound according to the following general formula (4):

wherein R¹⁵, R¹⁶, R¹⁶ and R¹⁹ are each independently hydrogen or methyl,provided that not all are methyl; R¹⁷O is one or more species ofC₂-C₄oxyalkylene groups, and in the case of two or more species, isoptionally block or random; w is an integer an average from 1 to 300; vand x are each independently an integer from 0 to 2; which contains 100weight parts of polycarboxylic acid copolymer and 10-50 weight parts ofpolyalkylene glycol in mixing proportion.
 2. A high strength concentratemix, comprising a cement mix and a cement additive according to claim 1.3. The high strength concrete mix of claim 2, wherein the amount ofcement additive is such that the amount of polycarboxylic acid copolymerto cement is 0.05-1.0% by weight based on the weight of cement, and theamount of the polyalkylene glycol to cement is 0.005-0.5% by weightbased on the weight of cement.
 4. A method of preparation of ahigh-strength concrete mix, comprising the incorporation into a concretemix a cement additive according to claim
 1. 5. The method of claim 4,wherein the amount of cement additive is such that the amount ofpolycarboxylic acid copolymer to cement is 0.05-1.0% by weight based onthe weight of cement, and the amount of the polyalkylene glycol tocement is 0.005-0.5% by weight based on the weight of cement.